The present invention relates to a diagnostic system that provides images of patients (objects) to be interpreted, and particularly tot the diagnostic system that provides the relationship between a direction (scan direction) along which a scan position is moved and an display order of tomographic images is improved. The diagnostic system is realized, for example, by an X-ray CT scanner capable of simultaneously scanning a plurality of slices of an object with scanning positions moved repeatedly, with the result that scan data of a plurality of slices are acquired at each scan position, then a plurality of tomographic images are obtained for diagnosis.
In facilities such as hospitals, an X-ray CT scanner is used as one of medical imaging modalities. The scanner includes two types of scanners referred to as a xe2x80x9csingle slice CTxe2x80x9d and a xe2x80x9cmulti-slice CT.xe2x80x9d
The single slice CT scanner is an imaging modality that can provide a single tomographic image by performing a single scan (a one-time scan for acquiring data necessary for image reconstruction). This CT scanner is normally used as follows. At a desired slice position, scanning is performed one time for acquiring raw data (that is, projected X-ray data or original data) of the one slice, then, for example, the tabletop on which a patient lies is moved for the next scan by a length corresponding to its slice thickness measured at the rotational center of an imaging region. At this new scan position, raw data for the adjacent or contiguous slice are acquired again. Repeating this scan and tabletop travel (alternatively, moving of the X-ray tube and X-ray detector) in sequence provides data of a plurality of tomographic images in a desired region of interest at intervals. Reconstructed tomographic images are displayed on a monitor in the reconstructed order. This scan is called xe2x80x9cmulti-scan.xe2x80x9d
On one hand, the multi-slice CT scanner is used for providing a plurality of images by the one-time scan. The number of images are usually agreed with that of detecting element rows in the slice direction of a two-dimensional X-ray detector used. For example, if the rows are five in the slice direction, raw data (projected data) of five slices can be acquired by the one-time scan.
The multi-scan can also be applied to multi-slice CT scanners. On having obtained raw data of a plurality of slices by performing the scan one time, the tabletop on which a patient lies is then moved in a scanning direction for the next scan by a length that corresponds to a total thickness of the slices (at the rotational center of an imaging region in the gantry). This can provide at a time raw data of a plurality of slices contiguous to the last plural slices.
The raw data of the plural slices are reconstructed with a given computation technique into a plurality of tomographic images, which are then displayed in the reconstructed order on a monitor. This repetition of scans and moving of the tabletop (or, moving of an X-ray tube and a detector) for a plurality of slices provides at intervals a plurality of tomographic images in a patient""s region to be diagnosed.
In CT examination, there is a diagnostic method that allows a doctor or others to interpret displayed tomographic images on a monitor, concurrently with scanning. Additionally, in the conventional CT examination, a direction (hereinafter, referred to as a scan direction) along which the scan position advances in one of the slice directions is normally fixed to a one way, but reversible. For instance, selectively driving a drive unit installed in a patient couch in either of two predetermined ways leads to arbitrary selection of the scan direction in either of a head-to-feet direction or a feet-to-head direction.
In the case that single slice CT scanners adopts a diagnostic method that allows the concurrent execution of imaging (scanning) and interpretation, it is enough that images are reconstructed in the scanned order and reconstructed images are then displayed in sequence, because only one image (tomographic image) is obtained for each scan. That is, independently from the scan directions, the diagnostic method is realized under a constant processing flow along which scanning, reconstruction, and display are carried out consecutively.
However, when such diagnostic method is applied to multi-slice CT scanners, there poses a problem described below.
Conventionally, since the scan direction has been set to one way, raw data of a plurality of slices acquired at a time by the multi-scan are reconstructed in a fixed slice position order advancing in the one way. For example, in each of three multi-scans A to C shown in FIG. 1A or 1D, the reconstructing orders are always set to xe2x80x9cslices A1, A2, A3, and A4; slices B1, B2, B3, and B4; and slices C1, C2, C3, and C4.xe2x80x9d Thus images are reconstructed and displayed in this order.
As understood from the figures, in the case of FIG. 1A, the order of reconstruction and display for slices accords with the scan direction xe2x80x9c1xe2x80x9d and becomes the order of xe2x80x9cA1, A2, A3, A4, B1, B2, . . . .xe2x80x9d Because the images appear in the order complying with the scan direction xe2x80x9c1xe2x80x9d, interpreting a plurality of images displayed in turn becomes are easier, providing interpreters three-dimensional, internal structure of a diagnostic region in an easily understandable manner.
In contrast, when the scan direction xe2x80x9c2xe2x80x9d is selected, the slices in the scan direction xe2x80x9c2xe2x80x9d proceed in the order of xe2x80x9cC4, C3, C2, C1, B4, B3, . . . ,xe2x80x9d while they are displayed in the order of xe2x80x9cC1, C2, C3, C4, B1, B2, . . . .xe2x80x9d
In other words, as to image display, slice images farthest from the front in the scan direction precedes those at the frontal side, providing observers (or interpreters) a feeling that the displayed images are spatially reversed. It is therefore difficult for observers to easily understand or grasp an internal structure of a diagnostic region three-dimensionally. This image observation imposes very troublesome, difficult work on observers. There is a fear that accuracy in interpretation may be lowered, in addition to increased interpretation work leading to lower efficiencies in interpretation
Furthermore, due to a fixed order to reconstruct and display images, the conventional image display technique is not useful, even if an operator wants to set the order in an arbitrary or highly flexible fashion.
The present invention has been made in consideration with the above problems. And one object of the present invention is to provide a diagnostic system (by way of example, which is realized by an X-ray CT scanner) capable of displaying images according to a specified or selected scan direction in performing the multi-scan, independently from in which way the scan direction is set, thus facilitating the three-dimensional understanding of an internal structure of a patient""s region to be diagnosed.
Another object of the present example is to remarkably enhance flexibility in setting an order along which images are reconstructed and then displayed in the multi-scan.
Still another object of the present invention is to not only remarkably enhance flexibility in setting a scan order along which images are displayed in the multi-scan but also display images along the scan direction, regardless of any scan direction, thus facilitating the three-dimensional understanding of an internal structure of a patient""s region to be diagnosed.
In the present invention, an order to reconstruct images (i.e., resulting in the order to reconstruct and display images: referred to as xe2x80x9creconstruction orderxe2x80x9d) and an order to display images (referred to as xe2x80x9cdisplay orderxe2x80x9d) are defined. Specifying either one of the reconstruction order or the display order permits images to be displayed on a display or monitor in a desired image-display order of slices scanned. That is, the reconstruction and display orders are parameters to control the image-display order.
In order to achieve the objects, as a first aspect of the invention, there is provided a diagnostic system having a display unit, comprising: means for performing scanning with an object to acquire data therefrom; means for producing a plurality of images from the data in a production order of the images; means for displaying on the display unit the plurality of images in response to producing each image; and means for setting the production order.
It is preferred that the production order setting means sets the production order for the plurality of images in accord with a scan direction along which the slice positions are moved every scan.
Another aspect of the present invention is that a diagnostic system having a display unit, comprising: means for performing scanning with an object to acquire data therefrom; means for producing a plurality of images from the data; means for displaying on the display unit the plurality of images in a display order of the images; and means for setting the display order.
It is preferred that the display order setting means sets the display order for the plurality of images in accord with a scan direction along which the slice positions are moved every scan.
Preferably, the image producing means produces the plurality of images whose slice positions differ from each other per one-time scan performed by the scanning performing means. Still preferably, the scanning performing means performs a plurality of times of scans as the slice positions are moved.
By way of example, the scanning performing means comprises an X-ray source irradiating an X-ray beam toward the object, a two-dimensional detector in which a plurality of arrays of detecting elements are arranged a plurality of rows in a slice direction of which one way is the scan direction for detecting the X-ray beam transmitted through the object, and data acquisition means outputting as the data projection data corresponding to a signal detected by the two-dimensional detector; and the image producing means includes reconstructing means reconstructing the images from the projection data.
For example, in the case of the first aspect, the production order setting means sets a reconstruction order of the images reconstructed by the reconstructing means. In the case of the second aspect, the display order setting means sets an order of the images displayed by the image displaying means.
Still preferably, the scan direction is a direction along which at least one of a tabletop on which the object lies and a gantry in which the scanning performing means is moved.
It is also preferred that the image producing means includes means for mutually binding image data of a plurality of slices contiguous in the plurality of slice positions for outputting as the images to the image displaying means.
It is also preferred that the image displaying means displays on the display unit the images one by one in turn according to the production order or the display order for the images. Still preferred is that the image displaying means displays on the display unit the images in a list mode on the screen thereof according to the production order or the display order for the images.
Therefore, no matte how the scan direction is set, the scanned images can be displayed on a display in a slice position order complying with the scan direction. A situation that images are displayed in the reversed order to the scan direction is surely avoided. A three-dimensional understanding of internal structures of an object""s region to be diagnosed can be performed in a steady, speedy and easy manner, contributing to an increase in accuracy of diagnosis and a reduction in operation work.
According to a third aspect of the present invention, provided is a diagnostic system having a display unit, comprising: means for performing scanning with an object to acquire data therefrom; means for producing a plurality of images from the data; means for displaying on the display unit the plurality of images; and means for displaying information about a display order of the images displayed by the image displaying means, the display order resulting from a processing order in either one of the image producing means and the image displaying means.
In this aspect, for example, the display-order information displaying means displays the display order information on the display unit also serving as a console monitor. Also it is preferred to further comprising means for setting the display order into an arbitrary order. By way example, the display-order setting means is means for manually setting as the display order information about a regular or random slice position of the object scanned by the scanning performing means.
Thus an operator is allowed to consider conditions of a region to be diagnosed in the stage of scan planning, and to decide the image-display order arbitrarily or in a flexible manner, based on how the conditions are. The image-display order thus-set can be visually confirmed there.
According to a fourth aspect of the present invention, there is provided a recording medium in which a diagnostic program is recorded, the program is used for achieving means for acquiring data by scanning an object; means for producing from the data a plurality of images; means for displaying the plurality of images; and means for setting an order of the plurality of images displayed by the displaying means, the display order resulting from a processing order in either one of the producing means and the displaying means.
The program recorded in the recording medium can be read by a computer installed in a diagnostic system, such as an X-ray CT scanner. On the basis of the program, the system can operate and provide the forgoing advantages inherently given the present invention.